Many app in Softaculous platform manage sensitive data (e-learning platforms, crm, erp, and so forth). Some data are stored to databases. According to GDPR, the admin should be able to provide to EACH user access to his/her own data ONLY. This function cannot be easily developed by whoever installed the app without the support of development team. It should be important which app is GDPR compliant and which is not since from today any installation that register sensitive data of EU citizens should be disabled if not GDPR compliant, in any part of world.

Applications are free to use.It's on user to Make his website compliant, and to write all the pages informing visitors about data protection.
There are already available modules (paid and free) which are adding some of needed GDPR compliancy, but remember that installing the module alone will not make you GDPR compliant.

Many of the apps do already have fuctionss/checkbox for agreeing "with whatever you need to operate", but it's on you that you specify with what they agree and what data are you collecting etc.
So no need for disabling instalations if the softaculous user does not know how to comply with the laws.